What does fault code TCM-040B mean?

Diagnostic fault code details for TCM-040B (Volvo C30 (2007–2013), Volvo C30 (2007–2013), Volvo C30 (2007–2013)). Repair service at OBD Tuning.

VOLVO

TCM-040B - Shift fork 2. faulty signal

System

Transmission Control Module (TCM)

Volvo models this fault code applies to

Applies to the following models:

4 models

C30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)

Show models by year and engine (10)

What does this fault code mean?

The transmission control module (TCM) has seen the signal from the position sensor for shift fork 2 change too quickly. The fault concerns that sensor, but whether the cause is in the sensor or in the transmission is shown by the other fault codes present.

Possible causes

Damaged position sensor
Incorrect voltage supply to the sensor
Damaged transmission control module (TCM)

What you can do

1Read out the fault codes from the transmission control module again to see whether the fault is in the transmission or in the mechatronic unit
2With diagnostic equipment, look at the position value for shift fork 2 in live data and see whether it changes unevenly when the gears are engaged
3If fault code TCM-042B is set, the cause is outside the mechatronic unit and a workshop should replace the transmission
4If any sensor code TCM-0408, TCM-0409 or TCM-040D is set but not TCM-042B, a workshop should replace the mechatronic unit
5If none of these codes is set, a workshop should check the input shaft speeds and the counter values to decide between a sensor and a mechanical fault

Symptoms you may notice5

Check engine light comes on or behaves abnormally
Text window with yellow warning symbol and message
Gear changes take too long to complete, sometimes or all the time
Gears shift too early, too late or too often, sometimes or all the time
No movement forward or in reverse with a gear selected

General guidance for car owners. Diagnosis on the car can point to a different cause.